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PO2 Dimensional Array Pointer
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  1. PO2 Dimensional Array Pointer
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    copied!<p>I am following an example to implement threads in C: <a href="http://ramcdougal.com/threads.html" rel="nofollow">http://ramcdougal.com/threads.html</a>. This example is using a 1-dimensional array. I need a dynamic 2 dimensional array.</p> <p>What would it look like if in the <code>main()</code> it was <code>int **array</code> instead of <code>int array[ARRAYSIZE]</code>?</p> <p>My problem is how to pass a pointer to a 2-dimensional array to the struct. The idea is, that I have a big array, and each thread should only fill a certain area of that array.</p> <p>Thanks a lot !</p> <p>Here's the code from the example:</p> <pre><code>struct ThreadData { int start, stop; int* array; }; void* squarer(struct ThreadData* td) { struct ThreadData* data=(struct ThreadData*) td; int start=data-&gt;start; int stop=data-&gt;stop; int* array=data-&gt;array; int i; for (i=start; i&lt;stop; i++) { array[i]=i*i; } return NULL; } int main(void) { int array[ARRAYSIZE]; pthread_t thread[NUMTHREADS]; struct ThreadData data[NUMTHREADS]; int i; int tasksPerThread=(ARRAYSIZE+NUMTHREADS-1)/NUMTHREADS; for (i=0; i&lt;NUMTHREADS; i++) { data[i].start=i*tasksPerThread; data[i].stop=(i+1)*tasksPerThread; data[i].array=array; } /* the last thread must not go past the end of the array */ data[NUMTHREADS-1].stop=ARRAYSIZE; /* Launch Threads */ for (i=0; i&lt;NUMTHREADS; i++) { pthread_create(&amp;thread[i], NULL, squarer, &amp;data[i]); } /* Wait for Threads to Finish */ for (i=0; i&lt;NUMTHREADS; i++) { pthread_join(thread[i], NULL); } /* Display Result */ for (i=0; i&lt;ARRAYSIZE; i++) { printf("%d ", array[i]); } printf("\n"); return 0; } </code></pre>
 

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